Synthesis of polycyclic alkanoic acid compounds



United States Patent 3,114,768 SYNTHESIS OF POLYCYCLEC ALKAN 01C ACID COMPGUNDS Henry E. Fritz, South Charleston, W. Va., assignor to gluon Carbide Corporation, a corporation of New ork No Drawing. Filed Sept. 25, 1961, Ser. No. 140,250 15 Claims. (Cl. Zed-515) This invention relates to a novel process for producing polycyclic alkanoic acid compounds. More particularly, this invention relates to a process for producing indenylalkanoic acids, fluorenylalkanoic acids, the group I alkali metal salts thereof, and the alkyl esters thereof.

The products produced by the process of this invention are polycyclic alkanoic acids: and the group I alkali metal salts and alkyl esters thereof, which can be represented by the following formula:

wherein R, when taken singly, is a hydrogen atom or a C H COOZ group; R when taken singly, is a hydrogen -atom; R and R when taken together, form a divalent CH=CH--CH=CH radical; Z is a hydrogen atom, a \group I alkali metal atom, or an alkyl radical having from about 1 to about 20 or more carbon atoms, such as methyl, ethyl, propyl, hexyl, Z-ethylhexyl, 2,2,4-trimethylpentyl, decyl, and the like; x is an integer having a value of from about 1 to about 15 or more, preferably from about 2 to about 6; and R is a hydrogen atom or a -C H COOZ group. Also included are the polycyclic alkanoic acid compounds which contain one or more hydrocarbon substituents on one or more of the ring carbon atoms.

Thus, it can be seen that the products of the process of this invention can be indenylalkanoic acid compounds and finorenylalkanoic acid compounds. The indenylalkanoic lacid compounds can be represented by the for- R2 xHnOO OZ wherein R can be a hydrogen atom or a C H COOZ group; and R x, and Z are previously defined.

The indenylalkanoic acid compounds produced by the process of this invention can be further represented by the following structural formulae:

H Cx ZxC 0 OZ (D) TO xHnC 0 0L H/\O xH2xC 0 OZ and l c xHZXC 0 OZ -H zoo OHQXCx CXHZXC 002 3,114,768 Patented Dec. 17, 1963 wherein x and Z are as previously defined. As illustrations of the indenylalkanoic acid compounds one can mention l-indenylacetic acid, 1,3-bis(carboXymethyDindene, 3-(l-indenyl)-propionic acid, l,3-bis(carboxyethyl)indene, l,1,3-tris(carboxyethyl)indenc, 4-(l-indenyDbutyric acid, l,3-bis(carboxypropyl)indene, 5-(1- indenyl)valeric acid, 1,3-bis(carboXybutyDindene, 6-(1- indenyl)caproic acid, 1,3-bis-(-carboXypentyDindene, 7 (l indenyl)enanthic acid, 1,3 bis(carboxyhexyl)indone, S-(I-indenyDcaprylic acid, 1,3-bis(carboxyheptyl) indene, 9-(l-indenyl)pelargonic acid, l,3-bis(carboxyoctyl)indene, 10-(1-indenyl)capric acid, 1,3-bis(carboxynonyDindene, lithium l-indenylacetate, sodium 1- indenylacetate, potassium l-indenylacetate, rubidium l-indenylacetate, cesium l-indenylacetate, lithium 3-(1- indenyDpropionate, sodium 3-( 1-indenyl)propionate, potassium 3-(1-indenyl)propionate, rubidium 3-(l-indenyDpropionate, cesium 3 (1 indenyl)propionate, lithium 4-(1-indenyl)valerate, sodium 4-(l-indenyl) valerate, potassium 4-(l-indenyl)valerate, rubidium 4-(l indenyDValerate, cesium 4 (l indenyl)valerate lithium 7-(1 -indenyl)enanthoate, sodium 7-(1-indenyl) enanthoate, potassium 7-( l-indenyDenanthoate, rubidium 7-( l-indenyl) enanthoate, cesium 7-( l -indenyl enanthoate, lithium 10-(l-indenyl)caprate, sodium IO-(I-indenyl) caprate, potassium 10- (1 --indenyl)caprate, rubidium 10-(1-indenyl)caprate, cesium l0-(l-indenyl)caprate, the dilithium salt of 1,3-bis(carboxymethyl)indene, the disodium salt of l,3-bis(carboxymethyl)indene, the dipotassium salt of 1,3-bis(carboxymethyl)indene, the diru'oidium salt of l,3-bis(carboxymethyl)indene, the dicesium salt of 1,3-bis(carboxymethyl)indene, the disodium salt of 1,3-bis(carboxypentyDindene, the dipotassium salt of 1,3-bis( carboxypentyDindene, the dirubidium salt or" l,3-bis(vcarboxypentyl)indene, the dicesium salt of 1,3-bis(carboxypcntyhindene, the dilithium salt of 1,3-bis(carboxynonyDindene, the disodium salt of 1,3-bis(carboxynonyl)indene, the dipotassium salt of 1,3-bis(carboxynonyl)indene, the diru'bidium salt of 1,S-bistcarboxynonyl)indene, the dicesium salt of 1,3-bis(carboxynonyl)indene, the trilithium salt of 1,1,3- tris(carboxyethyl)indene, the trisodium salt of 1,1,3- tris(carboxyethyl)indene, the tripotassium salt of 1,1,3- tris(carboxyethyl)indene, the trirubidium salt of 1,1,3- tris(carboXyethy-l)indene, the tricesium salt of 1,1,3- tris (carboxyethyl indene, methyl 3- 1-inder1yl)propio nate, octyl 3-(l-indenyl)propionate, the dimethyl ester of 1,3-bis(icarboxyethyDindene, the dioctyl ester of 1,3,-biscarboxyethyl indene, the trimethyl ester of 1 1,3-tris carboxyethyl indene, the trioctyl ester of l,1,3-tris(carboxyethyDindene, methyl 10-( l-indeny-l) caprate, octyl lO-(l-indenyDcaprate, the dirriethyl ester of l,3-bis(carboxynonyl)indene, the dioctyl ester of 1,3 bis(carboxynonyl)indene, 4 methyl 4 carboxymethyl)indene and its alkali metal salts and alkyl esters, 4-propyl-1-( carboxyethyl)indene and its alkali metal salts and alkyl esters, 4,6-dimethyl-l-(carboxyethyl)indene and its alkali metal salts and alkyl esters, 4-methyl- 1,3-bis(carboxyethyl)indene and its dialkali metal salts and dialkyl este"s, 4-methyl-l,1,3-tris(carboxyethyDindene and its trialkali metal salts and trialkyl esters, 3-(2-methyl 1 indenyl)propionic acid, 2 methyl 1,3- bis(carboxyethyl)indene, Z-methyl 1,1,3 tris(carboxyethyl)indene, 3-(2-phenyl-1-indenyl)propionic acid, 2- phenyl-1,3-bis('carboxyethyi)indene, 2 phenyl 1,1,3-tris (carboxyethyDindene, 3-(3-methyl 1 -indenyl)propionic acid, 3-methyl-1,l, 1-bis(carboxyethyl)indene, 3-phenyl- 1- carbonyethyl inden'e, 3-phenyl- 1, 1,1-bis-carboxyethylindene, and the like.

The fiuorenylalkanoic acid compounds that can be I produced by the process of this invention can be represented by the formula:

R OXI'IzxCO OZ wherein R, x, and Z are as previously defined.

The fluorenylalkanoic acid compounds can be further represented by the formulae:

(G) O [D 11 o XHZXO 0 Z and wherein x and Z are as previously defined. As examples of such fluorenylalkanoic acid compounds one can mention 9-fluorenylacetic acid, 3-(9-fluorenyl)propionic acid, 9,9-bis(carboxyethyDfluorene, 4-(9-fiuorenyl)butyric acid,

5- (9-fluorenyl)valeric acid, 6-(9-fluorenyl)caproic acid, 7-(9-fiuorenyl(enanthic acid, '8-(9-flu0renyl) caprylic acid, 9-(9-fluorenyl)pelargonic acid, 10-(9-fluorenyl) capric acid,

lithium 9-fluorenylacetate,

sodium 9-fluorenylacetate, potassium 9-fiuorenylacetate, rubidium 9-fluorenylacetate,

cesium 9-fluorenylacetate,

lithium 4-(9-fluorenyl)butyrate, sodium 4-(9-fluorenyl(butyrate, potassium 4-(9-fluorenyl)butyrate, rubidium 4-(9-fluorenyl) butyrate, cesium 4- (9-fluorenyl butyrate, lithium 7 -(9-fiuorenyl)enanthoate, sodium 7-(9-fluorenyl)enanthoate, potassium 7-(9-fluorenyl)enanthoate, rubidium 7-(9-fluorenyl)enanthoate, cesium 7-(9-fluorenyl)enanthoate, lithium 10-(9-fluorenyl)caprate, sodium 10- (9-fiuorenyl caprate, potassium l0-(9-fluorenyl)caprate, rubidium 10- 9-fluorenyl) caprate, cesium l0-(9-fiuorenyl)caprate,

the dilithium salt of 9,9-bis(carboxyethyDfluorene, the disodium salt of 9,9-bis(carboxyethyDfluorene, the dipotassium salt of 9,9-bis(carboxyethyl)fluorene, the dirubidium salt of 9,9-bis(carboXyethyDfluorene, the dicesium salt of 9,9-bis(carboxyethyDfluorene, methyl 3-(9- fluorenyl)propionate, octyl 3-(9-fiuorenyl)propionate, the dimethyl ester of 9,9-bis(carboxyethyDfiuorene, the dioctyl ester of 9,9-bis (carboxyethyhfluorene, methyl 10-(9-fluorenyl)caproate, octyl l0-(9-fiuorenyl)caproate, 2-methyl-9-carboxyethylfiuorene and its alkali metal salts and alkyl esters, 2-methyl-9,9-bis(carboxyethyl)fluorene and it dialkali metal salts and alkyl esters, 2,7-dimethyl- 9-carboxyethylfiuorene and its alkali metal salts and alkyl esters, 2,7-dimethyl-9,9-bis(carboxyethyl)fiuorene and its dialkali metal salts and dialkyl esters, and the like.

The compounds produced by the process of this invention are conveniently represented in the free acid form by the following formulae:

(I) Polycyclic alkanoic acids (III) l-indenylalkanoic acids 11 o x112x00 0 11 (IV) 1,3-bis (carboxyalkyl) indenes C XHnCOOH H C xHzx C OOH (V) 1, l ,3-tris (carboxyalkyl) indenes (VI) Fluorenylalkanoic acids It OXHEXC OOH (VII) 9-fiuorenylalkanoic acids H C H2 1C 0 O H (VIII) 9,9-bis(carboxyalky1)fluorenes HOOCHZXCX OxHhCOOI-I The compounds produced by the process of this invention are useful in themselves as polymerizable monomers for the production of polyesters, and they also can be used to prepare different monomers for the formation of polymeric products. For example, difunctional amino acids can be prepared by the nitration of the free acids or by the condensation of the free acids With acrylonitrile, followed by the reduction of the nitro or nitrile group to an amino group. Hydroxy acids can be produced by diazotization of this amino group Both the amino acids and the hydroxy acids are useful as monomers for the preparation of polymeric products.

The process of this invention comprises reacting a polycyclic compound represented by the formula:

with a carbonyloxy-containing compound, which can be a lactone represented by the formula:

or a hydroxy acid represented by the formula:

HOC H COOH wherein each R when taken singly, is a hydrogen atom; and, when taken together, form a divalent radical; x is as previously defined; and n is an integer having a value of 2 to 15 and preferably from 2 to 6. This reaction is carried out in the presence of a strong base.

The polycyclic starting materials are indene and fluorene. Included also are indenes and fluorenes that are substituted on a ring carbon atom with a hydrocarbon radical, provided said polycyclic starting material has a methylene (-CH group. Preferred substituents are alkyl radicals having from 1 to about 8 carbon atoms and aryl radicals having from 6 to about 8 carbon atoms. Illustrative of suitable polycyclic starting materials one can mention indene, fiuorene, 2-metl1ylindene, 3-methylindene, 4-methylindene, S-methylindene, 6-methylindene, 7-methylindene, 4-ethylindene, 2-propylindene, 3-propylindene, 4-propylindene, 5-propylindene, 6-propylindene, 7 propylindene, Z-phenylindene, 3-phenylindene, 4-phenylindene, 5-phenylindene, 6-phenylindene, 7-phenylindene, 2,3-dimethylindene, l-methylfiuorene, Z-methylfluorene, 3- methylfluorene, 4-methylfiuorene, S-methylfiuorene, 6- methylfiuorene, 7-methylfluorene, S-methylfiuorene, 1- ethylfiuorene, Z-ethylfiuorene, 3-ethylfluorene, 4-ethylfluorene, S-ethylfluorene, 6-ethylfiuorene, 7-ethylfiuorene, 8- ethylfluorene, l-propylfluorene, 2-propylfluorene, 3-propylfluorene, 4-propylfiuorene, 5-propylfiuorene, 6-propylfiuorene, 7-propylfiuorene, S-propylfluorene, 4,5-dimethylindene, 4-methyl-6-propylindene, 2,4-diethylfluorene, 2,4, 5,7-tetraethylfiuorene, and the like.

Illustrative of suitable lactones and hydroxy acids which can be employed as starting materials, one can mention propiolactone, butyrolactone, valerolactone, caprolactone, enanthiolactone, caprilolactone, pelargolactone, glycolic acid, 3-hydroxypropionic acid, 4-hydroxybutyric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 7-hydroxyenanthic acid, 8-hydroxycapri1ic acid, 9-hydroxypelargonic acid, lO-hydroxycapric acid, and the like.

When the desired primary product is the monocarboxylic acid polycyclic compound, the mole ratio of carbonyloXy-containing compound to polycyclic compound employed in the charge is about 1:1 or less. When a dicarboxylic acid polycyclic compound is desired as the primary product, the preferred mole ratio of carbonyloxycontaining compound to polycyclic compound is about 2:1. When a tricarboxylic indenylalkanoic acid compound is the primary product desired, the mole ratio of carbonyloxy-containing compound to indenyl compound is about 3:1 or more. Mole ratios between 1:1 and 2:1 give mixtures of monocarboxylic acids and dicarboxylic acids with both the indene and fiuorene compounds. Mole ratios between 2:1 to 3:1 with the indene compounds give mixtures of dicarboxylic indenylalkanoic acids and tricarboxylic indenylalkanoic acids.

In the process of this invention, a strong base is required to promote the reaction of the polycyclic compound with the carbonyloxy-containing compound. The strong base that is employed is a group I alkali metal hydroxide, such as lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide, with potassium hydroxide preferred.

Without limiting the invention to specific theories, it is believed that the reaction proceeds in two steps, (1) a reaction of the base with the carbonyloxy-containing compound to form an alkali metal salt of a hydroxy acid, and (2) a reaction of the alkali metal salt of the hydroxy acid with an active methylene group of the polycyclic compound whereby an alkali metal salt of a. polycyclic alkanoic acid is produced. Thus, to achieve good yields of polycyclic alkanoic acid compound at least one mole of base must be employed per mole of carbonyloxycontaining compound to promote the reaction. Furthermore, a slight excess of base acts as a catalyst for the reaction. Accordingly, mole ratios of base to carbonyloXycontaining compound of from 1:1 to 2:1 are generally employed, with mole ratios of from 1.1:1 to 1.5 :1 preferred. Higher ratios than these can be employed but afford no particular advantages.

The process of this invention is conducted at temperatures of from about 150 C., or lower, to about 350 C., or higher, with from about 200 C. to about 250 C. preferred.

In general, the process of this invention is conducted at atmospheric pressure. Higher and lower pressures can be employed but aiford no particular advantages.

The polycyclic alkanoic acid compounds produced by this invention are readily recovered as the alkali metal salts of the corresponding polycyclic alkanoic acid, and are isolated by procedures well known in the art. The corresponding free acids can be produced by acidifying the alkali metal salts, either before or after separation from the reaction mixture, and thereafter recovering the acids by procedures well known in the art.

The free acids, in turn, are readily converted to esters by reacting the free acid with an aliphatic alcohol having from about 1 to about 10 or more carbon atoms, such as methanol, ethanol, isopropanol, 2-ethylhexanol, 2,2,4- trimethylpentanol, decanol, and the like, according to procedures well known to one skilled in the art.

The following examples are illustrative.

Example I There were charged to a 3-liter, stainless steel, rocker autoclave a mixture of 332 grams of fiuorene, 340 grams of glycolic acid, and 400 grams of potassium hydroxide. The autoclave was sealed and the mixture was heated to 246 C. over a period of 2 hours and then maintained at 251 015 C. for 20 hours while agitating by rocking. The grey, solid reaction mixture containing potassium 9-fluorenylacetate was mixed with two liters of water and the resulting slurry was filtered to recover 166 grams of unreacted fiuorene. The aqueous filtrate was acidified to a pH of 2 with concentrated hydrochloric acid, whereby a grey solid containing 9-fiuorenylacetic acid precipitated. The precipitate was filtered from the acidic mixture and mixed with boiling toluene. The resulting slurry was filtered and the toluene was evaporated from the filtrate at reduced pressure, leaving 9-fiuorenylacetic acid which, after recrystallization from cyclohexane, weighed 40 grams and melted at 13'1132 C. The melting point of 9-fiuorenylacetic acid is reported by Bachmann and Sheenan, JACS, 62, 1687- (1940), as 131-132" C. Microanalysis: Calculated for C H O C, 80.3%; H, 5.4%; found: 80.2%; C, 5.5%. Neutralization equivalent: Theoretical: 224; found: 229. The structure of the 9-fiuorenylacetic acid was confirmed by its infrared and ultraviolet spectra.

Example II There was charged to a 3-liter, stainless steel, rocker autoclave 166 grams of fiuorene, grams of propiolactone, and 200 grams of potassium hydroxide. The autoclave was sealed and heated to 218 C. over a period of 1 hour and then maintained at 220 C. for 20 hours while agitating by rocking. The white, solid reaction 7 mixture containing the dipotassiurn salt of '9,9-bis(carboxyethyDfluorene was added to 1 liter of water and the resulting mixture was extracted 4 times with 500- milliliter portions of isopropyl ether. The ether extracts were combined and evaporated, whereby 121 grams of unreacted fluorene were recovered. The aqueous raflinate was acidified with concentrated hydrochloric acid to a pH of 2, whereupon 9,9-bis(carboxyethyl)fiuorene precipitated. The diacid was filtered from the aqueous acidic mixture, washed with water, and dried. There were obtained 70 grams of 9,9-bis(carboxyethyl)fluorene. Recrystallization of the acid from methanol gave white crystals which melted at 282284 C. (The melting point of 9,9-bis(carboxyethyl)fluorene is reported to be 273274 C., by H. A. Bruson, JACS, 64, 2457 (1942).) Microanalysis: Calculated for C H O C, 73.5%; H, 5.9%; found: C, 73.2%; H, 6.1%. Saponification equivalent: Theoretical: 155; found: 153. The structure of the acid was further confirmed by its infrared spectrum.

Example III There were charged to a 3-liter, stainless steel, rocker autoclave 332 grams of fiuorene, 190 grams of butyrolactone, and 200 grams of potassium hydroxide. The autoclave was sealed, pressurized to 25 p.s.i.g. with air, heated to 225 C. over a period of one hour, and then maintained at 225 C. for 22 hours while agitating by rocking. The resulting white, solid reaction mixture containing potassium 4-(9-fluorenyl)-butyrate was added to 1 liter of water and the resulting slurry was filtered to recover 171 grams of unreacted fluorene. The aqueous filtrate was acidified to a pH of 1 with concentrated hydrochloric acid, whereupon 4-(9-fluorenyl)butyric acid separated as an oil which slowly crystallized on standing. After filtering the crystals, washing with water, and drying, the 4-(9-fiuorenyl)butyric acid weighed 168 grams and melted at l23l32 C.

The methyl ester of 4-(9-fluorenyl)butyric acid was produced by refluxing for 48 hours a mixture of 90 grams of 4-(9-fiuorenyl)butyric acid with 500 milliliters of methanol and 5 grams of para-toluenesulfonic acid as a catalyst. The reaction mixture was fractionally distilled and 75 grams of methyl 4-(9-fluorenyl)butyrate was recovered as a fraction boiling at 166 to 170 C. at 0.4

millimeter mercury presure. The methyl ester has a refractive index, 11 of 1.5927. Microanalysis: Calculated for C H O C, 81.2%; H, 6.8%; found: C, 81.3%; H, 7.0%. Saponification equivalent: Theoretical: 266; found: 263.

The structures of 4-(9-fluorenyl)butyric acid and methyl 4(9-fluorenyl)butyrate were further confirmed by their infrared and ultraviolet spectra.

Example IV There were charged to a 3-liter, stainless steel, rocker autoclave, 830 grams of fiuorene, 550 grams of valerolactone, and 365 grams of potassium hydroxide. The autoclave was sealed, pressurized to 25 p.s.i.g. with air, heated to 215 C. over a period of 2 hours, and then maintained at 220 C15 C. for 19 hours while agitating by rocking. After cooling, the white, solid reaction mixture containing potassium 5-(9-fluorenyl)valeratewas added to 2 liters of water. The resulting slurry was filtered to recover 90 grams of unreacted fluorene. The aqueous filtrate was acidified with concentrated hydrochloric acid to a pH of 1, whereupon 5-(9-fiuorenyl) valeric acid separated as oil. The oil was extracted with 500 milliliters of a benzene-isopropyl ether mixture containing 50% isopropyl ether. The benzene-isopropyl ether layer was washed with 200 milliliters of 8 aqueous hydrochloric acid and then several times with 200-milliliter portions of water. The isopropyl ether and benzene were evaporated from the water-washed solution, leaving 1110 grams of 5-(9-fluorenyl)valeric acid.

Methyl 5-(9-fiuorenyl)valerate was produced by refluxing 300 grams of 5-(9-fluorenyl)valeric acid with 1500 milliliters of methanol and 15 grams of para-toluenesulfonic acid -as catalyst for 26 hours. The resulting reaction mixture was Washed with water, 10% aqueous sodium hydroxide, and again with water. The Washed reaction mixture was fraction-all distilled and methyl 5-(9-fluorenyl)valerate was recovered as a fraction boiling at 212 C. at a pressure of 3 millimeters of mercury. The methyl 5-(9-fluorenyl)valerate thus recovered had a refractive index 11 of 1.5863. Microanalysis: Calculated for C H O C, 81.4%; H, 7.2%; found: C, 80.8%; H, 7.0%. Saponification equivalent: Theoretical: 280; found: 280.

The trimethylpentyl ester was prepared in a similar mamrer, except that 2,2,4-trimethylpentanol was used in place of methanol. 2,2,4-trimethylpeutyl 5-(9-fluorenyl) valerate was recovered as a fraction boiling at 270 C. at 10 millimeters of mercury. The refractive index, n of the trimethylpentyl ester was 1.5462. Microanalysis: Calculated for C H O C, 82.5%; H, 9.1%; found: C, 82.5%; H, 8.9%. Saponification equivalent: Theoretical: 378; found: 377.

The structures of the acid and both esters were further confirmed by their infrared and ultraviolet spectra.

Example V There were charged to a 1-liter, stainless steel, rocker autoclave 74.7 grams of fiuorene, 63 grams of caprolactone, and 45 grams of potassium hydroxide. The autoclave was sealed, pressurized to 25 p.s.i.g. with air, heated to 225 C. over a period of 1 hour, and then maintained at 225 C.i5 C. for 20 hours, while agitating the mixsure by rocking. The maximum pressure in the autoclave was p.s.i.g. After cooling to ambient temperature, the light tan solid containing potassium 6-(9-fiuorenyl)caproate was removed from the autoclave and added to 400 milliliters of water. The resulting aqueous mixture Was extracted with two ISO-milliliter portions of isopropyl ether to remove unreacted fluorene. The aqueous rafiinate was acidified with concentrated hydrochloric acid to a pH of 2 and 6(9-fluorenyl)caproic acid separated as a viscous oil. The 6-(9-fluorenyl)caproic acid was not appreciably soluble in ether or hexane but was readily soluble in alcohols. The yield of 6-(9-fluorenyl) caproic acid was grams.

Methyl 6-(9-fluorenyl)caproate was produced by refluxing approximately 100 grams of 6-(9-luorenyl)caproic acid with 300 milliliters of methanol and 5 milliliters of concentrated sulfuric acid for 4 hours. The reaction mixture was fractionally distilled and the methyl ester was recovered as a fraction boiling at 19.5-197" C. at a pressure of 1 millimeter of mercury. The index of refraction, 11 of the methyl 6-(9-fluorenyl)caproate was 1.5785. The saponification equivalent of the ester was 284; theoretical value is 294. The structure of the ester was confirmed by its infrared and ultraviolet spectra.

In a similar manner 6-(9-fluorenyl)caproic acid or its alkali metal salts or alkyl esters is produced by substituting 6-hydroxycaproic acid for caprolactone.

Example VI There were charged to a 3-liter, stainless steel, rocker autoclave 129 grams of indene, 139 grams of caprolactoneand 100 grams of potassium hydroxide. The autoclave was sealed and purged with nitrogen, after which the reaction mixture was heated for 20 hours at 200 C.i2 C. while agitating by rocking. The solid reaction product containing a mixture of potassium 6-(1-indenyl)caproate and the dipotassium salt of 1,3-bis-(carboxypentyl) indene was dissolved in water and filtered to remove traces of solid impurities. The aqueous filtrate was extracted once with 250 milliliters of isopropyl ether to remove any unreacted indene. The aqueous solution was then cooled with 500 grams of ice and acidified with concentrated hydrochloric acid to a pH of 2, whereupon an oil separated which slowly changed to a semi-solid. The semi-solid Was separated from the water, dissolved in 500 milliliters of isopropyl ether, and filtered. The ether was evaporated from the filtrate, leaving 191 grams of an oil which was a mixture of 6-(1-indeny1)caproic acid and 1,3-bis(carboxypentyl)indene. The two acids. are readily separated by a fractional distillation at reduced pressures.

The 6-(1-indeny-l)caproic acid and 1,3-bis(-c arboxypentyl)indene were converted to their methyl esters by refluxing the product obtained above with 500 milliliters of methanol and 5 grams of para-toluenesulfonic acid for hours. The resulting reaction mixture was washed with 1 liter of Water and then extracted twice with 250- milliliter portions of isopropyl ether. The ether extracts were combined and then extracted twice with 250-milliliter portions of isopropyl ether. The ether extracts were combined and washed with 100 milliliters of 5% aqueous sodium hydroxide and then with water until the ether solution was neutral. The ether solution was distilled to remove the ether, the residue was fractionally distilled at reduced pressure, and two fractions were obtained. The 1ower-boiling fraction, which weighed 48 grams, was obtained at 161-188" C. at 0.5 $0.1 millimeter of mercury pressure and Was redistillecl to yield 40 grams of methyl 6-(1indenyl)caproate, which boiled at 145 C. at 0.45 millimeter of mercury pressure. The index of refraction, r1 of the methyl 6-(1-indenyl)-caproate was 1.5327. Microanalysis: Calculated for G i-1 0 C, 78.7%; H, 8.3%; found: 78.3%; H, 8.4%. The higher boiling fraction, which weighed 61 grams, was obtained at 188234 C. and 0.5 10.1 millimeter of mercury pressure and was redistilled to yield 38 grams of the dimethyl ester of 1,3-bis(carboxypentyl)indene, which boiled at 222 C. at 0.47 millimeter of mercury pressure. The index of refraction, 12 of the dimethyl ester was 1.5250. Microanalysis: Calculated for C H O C, 74.2%; H, 8.6%; found: C, 74.7%; H, 8.5%.

In a similar manner, 3-(l-ind enyl)propionic acid or its alkali metal salts and esters, 1,3-bis (carboxyethyl)indene or its alkali metal salts and esters, or l,l,3-tris(carboxyethyl)-indene or its alkali metal salts and esters can be produced by substituting propiolactone or S-hydroxypropionic acid for caprolaotone.

What is claimed is:

1. In a process for producing a polycyclic alkanoic acid compound represented in the free acid form by the formula:

wherein R, when taken alone, is a member selected from the group consisting of a hydrogen atom and a -C H COOH radical; R when taken alone, is a hydrogen atom; R and R when taken together, are the divalent -CH=CHCH=CH- radical; R is a member selected from the group consisting of a hydrogen atom and a -C H COOH radical; and x is an integer having a value of from 1 to 15, the step which comprises heating at a temperature of from 150 C. to 350 C. a mixture of a polycyclic hydrocarbon compound represented by the formula:

wherein each R when taken alone, is a hydrogen atom, and when taken together, are the divalent radical, a carbonyloxy-containin-g compound selected from the group consisting of a lactone represented by and a hydroxy acid represented by the formula:

HOC H COOH wherein n is an integer having a value from 2 to 15 and x is as previously defined, and at least 1 mole of a group I alkali metal hydroxide per mole of carbonyloxy-containing compound.

2. In a process for producing an indenylalkanoic acid compound represented in the free acid form by the formula:

and a hydroxy acid represented by the formula:

HOC H COOH wherein n is an integer having a value of from 2 to 15 and x is as previously defined, and at least 1 mole of a group I alkali metal hydroxide per mole of said carbonyloxy-containing compound.

3. In a process for producing a l-indenylalkanoic acid compound represented in the free acid form by the formula:

H C xHZxCOOII wherein x is an integer having a value of from 1 to 15, the step which comprises heating at C. to 350 C. a mixture of indene, a carbonyloxy-containing compound selected from the group consisting of a lactone represented by the formula:

and a hydroxy acid represented by the formula:

HOC H COOH wherein n is an integer having a value of from 2 to 15 and x is as previously defined, and at least 1 mole of a group I alkali metal hydroxide per mole of said carbonyloxy-containing compound.

4. The process for producing a l-indenylalkanoic acid compound as claimed in claim 3 wherein said carbonyloxy containing compound is caprolactone.

5. In a process for producing a 1,3-bis(carboxyalkyl)- indene compound represented in the free acid form by the formula:

OxH2xC 0 OH H C ZxC O OH 1 1 wherein x is aninteger having a value of from 1 to 15, the step which comprises heating at 150 C. to 350 C. a mixture of indene, a carbonyloxy-containing compound selected from the group consisting of a lactone represented by the formula:

| -C=O C anand a hydroxy acid represented by the formula:

HOC H COOH alky1)indene compound represented in the free acid form by the formula:

HOOGHZXC x CxHhCOOH wherein x is an integer having a value of from 1 to 15, the step which comprises heating at 150 C. to 350 C. a mixture of indene, a carbonyloxy-containing compound selected from the group consisting of a lactone represented by the formula:

and a hydroxy acid represented by the formula:

HOC H COOH wherein n is an integer having a value of 2 to and x is as previously defined, and at least 1 mole of a group I alkali metal hydroxide per mole of said carbonyloxycontaining compound.

8. In a process for producing a fluorenylalkanoic acid compound represented in the free acid form by the formula: V

CxHnCOOH wherein R is a member selected from the group consisting of a. hydrogen atom and a C H COOH radical; and x is an integer having a value of from 1 to 15, the step which comprisw heating at 150 C. to 350 C. a mixture of fluorene, a carbonyloxy-containing compound selected from the group consisting of a lactone represented by the formula:

and a hydroxy acid represented by the formula:

HOC H COOH wherein n is an integer having a value of from 2 to 15 and x is as previously defined, and at least 1 mole of a group I alkali metal hydroxide per mole of said carbonyloxy-contain-ing compound.

9. In a process for producing a 9-fluorenylalkanoic acid compound represented in the free acid form by the formula:

H CXHZxCOOH wherein x is an integer having a value of from 1 to 15, the step which comprises heating at C. to 350 C. a mixture of fluorene, a carbonyloxy-containing compound selected from the group consisting of a lactone represented by the formula:

E-O-C=O C Hu and a hydroxy acid represented by the formula:

HOC -H COOH wherein n is an integer having a value of from 2 to 15 and x is as previously defined, and at least 1 mole of a group I alkali metal hydroxide per mole of said carbonyloxy-containing compound.

10. The process for producing a 9-fiuorenylalkanoic acid compound as claimed in claim 9 wherein said carbonyloxy-containing compound is glycolic acid.

11. The process for producing a 9-fluorenylalkanoic acid compound as claimed in claim 9 wherein said carbonyloxy-containing compound is butyrolactone.

12. The process for producing a 9-fluorenylalkanoic acid compound as claimed in claim 9 wherein said carbony loxy-containing compound is valerolactonc.

13. The process for producing a 9-fiuorenylalkanoic acid compound as claimed in claim 9 wherein said carbonyloxy-containing compound is caprolactone.

14. In a process for producing a 9,9-bis(carboxya1kyl)- fiuorene compound represented in the free acid form by the formula:

wherein x is an integer having a value of from 1 to 15, the step which comprises heating at 150 C. to 350 C. a mixture of fluorene, a canbonyloxy-containing compound selected from the group consisting of a lactone represented by the formula:

o-o C 2H2n and a hydroxy acid represented by the formula:

HOC H COOH whe rein n is an integer having a value of from 2 to 15 and x is as previously defined, and at least 1 mole of a group I alkali metal hydroxide per mole of said carbonyloxy-containing compound.

15. The process for producing a 9,9-bis (carboxyalkyl)- fluorene compound as claimed in claim 14 wherein said carbonyloxy-containing compound is propiolactone.

References Cited in the tile of this patent UNITED STATES PATENTS 2,280,058 Bruson Apr. 21, 1942 2,301,518 Bruson Nov. 10, 1942 FOREIGN PATENTS 562,391 Germany Nov. 1, 1932 OTHER REFERENCES Rieveschl et'al.: Chem. Rev, vol. 56, pages 287-389 (1938). 

1. IN A PROCESS FOR PRODUCING A POLYCYCLIC ALKANOIC ACID COMPOUND REPRESENTED IN THE FREE ACID FORM BY THE FORMULA: 